In the related art, a technology of the field described above is disclosed in Japanese Patent No. 3134694. In the seat disclosed in this publication, recessed seams extending in a fore-and-aft direction are provided at boundaries between a major seating surface and side surfaces disposed on both sides thereof. The recessed seam is formed by pulling part of the cover inward of the seat by passing a wire provided on a cushion side through a loop portion provided on the cover side. However, this configuration has a problem that operation for passing the wire through the loop portion is troublesome. Accordingly, with a seat disclosed in Japanese Patent No. 3779028, a hook and loop fastener half is joined to the cover side by sewing at the recessed seam, and a hook and loop fastener half is fixed to a cushion material side by adhesion. When attaching the cover to the cushion material, the hook and loop fastener half on the cover side is pressed against the other hook and loop fastener half on the cushion material from above. With this operation, the recessed seam may be formed on the seat easily.